this is the video that convinced me jet fuel didn't bring the buildings down.
Steel beam horseshoed with no cracking.
19m54s
I thought the 'official story' was fuel oil fires weakened the steel, and global collapse ensued.
fuel oil fires don't hit 1000's of degrees.
thermite/thermate (nano)
all you would need to do is progressively weaken key supports (cutting cross beams) and the building will collapse under it's own weight and look natural.
Jonathan Cole - 9/11 Experiments: The Great Thermate Debate